When I lived in the dorms, I happened to be in the hallway one day, the first week of school, when an RA popped out of the stairwell, looked around like she smelled something funny, walked up to the door in front of her and sniffed, then bolted back into the stairwell.
I knocked on the door in question. The guy answered, hiding a joint behind his back. I told him what happened.
15 minutes later, the RA returned with a campus cop. He told them he'd been out and only just returned 5 minutes before. He thought he smelled something funny too, but it was much fainter now, and smelled a lot more like straight cigarettes (which were allowed) and he wasn't sure, since he'd just gotten there and his roommate wasn't there. :shrug:
I'd made a friend for life, or at least until he got expelled for his grades. :shrug: It doesn't hurt to have someone in your corner, even if he is a stoner.